1. Technical Field
The present invention relates to a circuit device, an electro-optical device, an electronic apparatus, and the like.
2. Related Art
Nowadays, color liquid crystal panels (display panels) are often used in electronic apparatuses such as monitors, TVs, and notebook computers. In the color liquid crystal panel, each pixel is constituted by R, G, and B subpixels, for example, and one pixel, as a whole, expresses one color by combining colors of the R, G, and B subpixels. The colors of the R, G, and B subpixels are each determined by the luminance of light that has passed through a color filter provided thereon. The luminance of light that passes through each color filter is determined by a voltage supplied to a corresponding source electrode (data line) of the liquid crystal panel. This voltage is referred to as a tone voltage. The electronic apparatus is provided with a display driver including a circuit device that drives the liquid crystal panel by controlling the tone voltage.
In general, the input (such as an input voltage or an input signal) and the output (such as light transmittance or brightness) in the liquid crystal panel are not in a linear direct proportional relationship. Each liquid crystal panel has its own specific gamma characteristic (luminance characteristic) resulting from the liquid crystal material that is used and variations in manufacturing. Also, in the same liquid crystal panel, R, G, and B gamma characteristics are different. That is, even in the case where the same tone voltage is supplied to each of the R, G, and B subpixels in the same liquid crystal panel, R, G, and B tones are different. Therefore, tone voltages in which consideration is given to the R, G, and B gamma characteristics of the liquid crystal panel need to be supplied to the source electrodes of the liquid crystal panel in order to express desired tones.
For example, in JP-A-2004-29795, a circuit device in which R, G, and B tone voltage generation circuits are separately provided is disclosed. These R, G, and B tone voltage generation circuits respectively generate R, G, and B multiple tone voltages. R, G, and B decoders respectively output voltages selected from the R, G, and B multiple tone voltages based on display data, via amplifiers to the display panel, and as a result, the display panel is driven.
Also, in the known technology in JP-A-2006-39205, tone characteristics of the tone voltages (gamma curves) are corrected by adjusting resistance values of the resistors that constitute a ladder resistor in the tone voltage generation circuit.
In the known technology disclosed in JP-A-2004-29795, since the R, G, and B tone voltage generation circuits are separately provided, the circuit area of the overall tone voltage generation circuit increases. Also, R, G, and B multiple tone voltage lines need to be separately provided, and as a result, the circuit area increases as well. Therefore, in the known technology disclosed in JP-A-2004-29795, the scale of the circuit device increases, which incurs a problem such as an increase in cost.
Therefore, it is desirable that tone voltages that are supplied from the tone voltage generation circuit are used in common for pieces of R, G, and B display data (first color component display data, second color component display data, and third color component display data). In such a case, tone voltages that are to be output need to be selected from the tone voltages that are used in common so as to adapt to the R, G, and B gamma characteristics.
On the other hand, in JP-A-2006-39205, processing in the case where tone voltages generated by the tone voltage generation circuit are used in common for pieces of R, G, and B display data is not disclosed.
Also, in the case where tone voltages generated by the tone voltage generation circuit are used in common for pieces of R, G, and B display data, a case is conceivable where the circuit device supplies tone voltages for at least two color components among R, G, and B tone voltages to the liquid crystal panel at the same time. In this case, when white balance is adjusted, for example, coloring, a tone skip, or the like may occur at a specific tone. That is, tone properties or color reproducibility may degrade at a specific tone. This is caused by, among the tone voltages that are supplied to the liquid crystal panel at the same time, a tone voltage for one piece of color component display data being too high or too low relative to a tone voltage for the other piece of color component display data that is supplied at the same time, or the like.